The *file* delivery agent (the * characters are part of the name) handles delivery to files. The *include* delivery agent handles delivery through :include: lists. Neither can be considered a true delivery agent, however, because actual delivery is still handled internally by sendmail. Instead, they provide a way to tune delivery agent behavior for these two delivery needs.

The defaults for these delivery agents are predefined. They can be viewed with the following command (note that output lines are wrapped to fit the page):^[6]

^[6] Note that when sendmail prints an S='s or R='s number/number, it will automatically print the delivery agent name associated with each number, if there was one. Thus, the parse/parse in the example does not mean R=parse/parse was in the configuration file. It means only that R=0/0 was in the configuration file (or was omitted), and that the parse rule set happens to be numbered 0. Recall that an S='s or R='s value of 0 means that no rule set will be called.

% /usr/sbin/sendmail -d0.15 -bt < /dev/null | egrep "file|include"
mailer 1 (*file*): P=[FILE] S=parse/parse R=parse/parse M=0 U=0:0 F=9DEFMPloqsu L=0 
E=\n T=X-Unix/X-Unix/X-Unix r=100 A=FILE $u
mailer 2 (*include*): P=/dev/null S=parse/parse R=parse/parse M=0 U=0:0 F=su L=0 E=\n 
T=<undefined>/<undefined>/<undefined> r=100 A=INCLUDE $u

These predefined defaults can be overwritten, however, by declaring *file* and *include* in the configuration file. For example, the following configuration file declaration overrides the internal definition shown earlier, and limits the size of any mail message that is delivered to files to 1 megabyte:

M*file*, P=[FILE], M=1000000, F=9DEFMPloqsu, T=X-Unix/X-Unix/X-Unix, A=FILE $u

Note that any delivery agent equate that does not default to zero (such as the P=, F=, T=, and A= delivery agent equates) needs to be copied to this configuration file declaration, or the original value will be lost.

A similar change in definition for the mc configuration of V8 sendmail would look like this:

MAILER_DEFINITIONS
M*file*, P=[FILE], M=1000000, F=9DEFMPloqsu, T=X-Unix/X-Unix/X-Unix, A=FILE $u